Polymeric dyes are widely disclosed in the literature. Of particular importance is their use as food colorings and in the bulk and surface coloring of plastic objects and textile fibers. Their use as hair dyes, as tinting agents in paper manufacture, and in imaging systems as sensitizing agents is known in the art.
Polymeric monocarbocyanine dyes useful as silver halide sensitizers are disclosed in U.S. Pat. Nos. 2,425,772 and 2,465,774. The cyanine dye moieties are joined by hydrocarbon chains through their ring nitrogens.
In U.S. Pat. Nos. 3,245,965 and 3,293,075 polyphthalocyanines are disclosed to be useful as semiconducting thin films which because of their insolubility must be formed by chemical reaction in situ.
U.S. Pat. No. 4,365,012 discloses photochromic cyclic polyimides for optical recording.